Currently, multiple advanced radio access technologies (Multiple Radio Access Technology: Multi-RAT) coexist, enabling a user terminal to access a wireless network at a high speed and enjoy high-quality services. Typical technologies include wireless wide area network access technologies represented by Long Term Evolution (LTE) and wireless local area network technologies represented by Institute of Electrical and Electronics Engineers (IEEE) 802.11. Wireless Local Area Networks (WLAN) is a network established using a wireless communication technology within a certain local area. The schematic diagram of the architecture of WLAN is shown in FIG. 1. As compared with LTE, WLAN has a small coverage, a high access rate, and a low usage cost.
The LTE network, as a typical network in the 3rd Generation Partnership Project (3GPP) wireless communication family networks, includes an Evolved Universal Terrestrial Radio Access (E-UTRAN) base station eNB (Evolved NodeB) and an Evolved Packet Core (EPC). The network is flattened. The E-UTRAN includes a set of eNBs connected to the EPC through an S1 interface, and the eNBs may be connected with each other through X2. The S1 and X2 are logical interfaces. One EPC may manage at least one eNB, one NodeB may also be controlled by multiple EPCs, and one eNB may manage at least one cell. The Long Term Evolution Advanced (LTE-A) system evolves from the LTE system, and the network architecture is consistent with LTE. The LTE uses 4G technologies. As compared with 3G, LTE has many technical advantages, such as a higher data rate, a lower latency transmission and guaranteed Quality of Service (QoS). As compared with the WLAN, LTE has a broader coverage, and may support high-speed mobility and roaming of the user terminal.
With the continuous evolution of future communication networks, coexistence of multiple standard network modes is an unavoidable trend, including converged networking (fusion networking) of 2G, 3G and LTE, converged networking of 3GPP-WLAN, and so on. The schematic diagram of the converged networking of LTE-WLAN is shown in FIG. 2. Due to complementary feature(s) of WLAN and 3GPP wireless communication family networks, interconnection and internetworking of 3GPP-WLAN have become one of the hot issues among device manufacturers, system integrators, operators and research institutes. The basic principle is to minimize the impact on existing standards and systems of WLAN and 3GPP, that is, to keep the WLAN standard unchanged and to minimize the modification to the existing 3GPP specifications. The key for interconnection and comprehensive structure design between 3GPP and WLAN is to provide interaction functions between 3GPP and WLAN based on the IEEE 802.11 standard.
The interconnection between 3GPP and WLAN is based on a direct interface between the two systems. “Wireless LAN Termination” (WT) is defined as a termination point of a LTE-WLAN interface Xw at the WLAN system side. The WT may be a logical entity, may be an independent network element, or may be implemented on a Wireless Access Point/Wireless Access Controller (AC/AP). Multiple WLAN access network elements may be connected under the WT. When a user accesses the 3GPP system, such as the LTE eNB, LTE-WLAN aggregation operations may be implemented by establishing, modifying, or deleting the WT. Both the LTE and WLAN systems provide data transmission for UEs, thereby user throughput and network capacity are improved.
Therefore, when 3GPP and WLAN are integrated or converged, how to realize 3GPP-WLAN aggregation so as to achieve offload under a cross-system scenario is an urgent problem.
This section provides background information related to the present disclosure which is not necessarily prior art.